1. Field of the Invention
The invention relates to an exhaust heat recovery system for recovering heat energy in gas, and may be used, for example, in a vehicle like a hybrid vehicle, for converting recovered heat energy from a gas to electric energy.
2. Description of the Related Art
Heat energy is contained within exhaust gas, and the like, that is discharged from an engine of an automobile. Accordingly, if the exhaust gas is simply discharged, the energy is wasted. To address this concern, technologies have been developed that utilize an exhaust heat recovery system to recover the heat energy contained in the exhaust gas, and convert it to electric energy using a thermoelectric conversion element. The converted electric energy can then be used, for example, to recharge a battery.
An example of such a technology for recovering heat energy in an automobile is the fuel recycling system disclosed in Japanese Patent Laid-Open Publication No. 2001-068138. In this fuel recycling system, heat generated by a fuel cell in a fuel cell vehicle is absorbed using a chemical heat pump. Then, the absorbed heat is liberated in an exothermic reaction that is utilized to perform a dehydrogenation-reaction in which hydrogen is separated from a hydrate.
Note that, the above described exhaust heat recovery system can potentially be improved to enable more heat energy in the exhaust gas to be recovered. To achieve this, a configuration can be proposed in which a heat pump is used to recover the heat energy, thus allowing the recovery rate of the heat energy in the exhaust gas to be raised, and the amount of electric power generated by the thermoelectric conversion element to be increased.
However, the fuel recycling system disclosed in Japanese Patent Laid-Open Publication No. 2001-068138 simply uses the chemical heat pump to enable the heat generated from the fuel cell to be used as heat for the dehydrogenation reaction. Accordingly, the disclosed configuration does not conceive of the idea of using a heat pump to transfer heat so that the heat energy contained in the exhaust gas can be converted to electric energy.